齐岳山隧道岩溶发育特征与溶洞处治技术研究

为解决复杂岩溶隧道溶洞处治难题，以利万高速公路谋道连接线工程齐岳山隧道为依托，调研隧道施工过程中揭露的26处溶洞，分析溶洞的发育规模、充填特性、含水特性、发育位置与地质成因，采用数值模拟的方法研究特大型溶洞对隧道围岩变形的影响规律，通过案例分析探讨隧道不同位置溶洞处治技术。结果表明： 1）隧道揭露中型溶洞最多，大型溶洞次之，小型和特大型溶洞最少，揭露溶洞多为无充填或部分充填的干溶洞，发育位置主要集中于掌子面; 2）隧址区气候和水文地质条件利于岩溶发育，但由于隧道高程较高，地下水位接近或低于隧道设计标高，未揭露含水溶洞; 3）溶洞与隧道交接部位隧道围岩位移量最大，需加强支护; 4）形成隧道不同位置、不同规模溶洞的处治技术与原则并应用到工程实际中，后期运营结果证明溶洞处治效果良好。 溶洞处治应建立规范化超前探测、标准化处治流程、模块化处治技术及针对性处治方案。

Development Characteristics and Treatment Techniques of Karst Caves in Qiyueshan Tunnel

In this paper, a case study is conducted on the Qiyueshan tunnel of the Moudao connecting line project on the Lichuan Wanzhou expressway. The conditions of the 26 karst caves exposed during tunnel construction are investigated, and the development scale, filling characteristics, water bearing characteristics, development location, and geological origin of karst caves are analyzed. Furthermore, the influence of the super large karst cave on the tunnel surrounding rock deformation is studied using numerical simulation, and the treatment technologies of karst caves in different positions of the tunnel are discussed through case analysis. The results reveal the following: (1) In exposed karst caves, the medium scale one is the most common, followed by large scale one, and the small scale and super large scale ones are the least common; the exposed karst caves are mostly dry with no or partial filling, and the development location mainly concentrates on the tunnel face. (2) The climate and hydrogeological conditions at the tunnel site are favorable for karst development, but due to the high tunnel elevation and groundwater level lower than the design level, no water bearing karst cave is exposed. (3) The surrounding rock displacement at the junctions between the karst cave and tunnel is the largest, so the support should be strengthened. (4) The treatment techniques and principles of karst caves of various sizes and locations are developed and applied to engineering practice. The subsequent operation results validate the feasibility of the treatment methods. It is proposed that normalized advance detection, standardized treatment process, modular treatment technique, and targeted treatment scheme should be established for karst cave treatment.